Image information recording apparatus

ABSTRACT

An image information recording apparatus, in which a light beam is modulated by an information signal to effect recording on a recording medium, includes a light beam forming device, a modulator for modulating the light beam from the light beam forming device in accordance with an image-information signal, an image-forming lens system for focussing the light beam from the modulator upon the recording medium, devices for sensitizing the recording medium, a scanning system for causing the modulated light beam to scan over the recording medium, and a system for overlaying the image information and other image information with respect to the recording medium.

This application is a continuation of application Ser. No. 935,987 filedAug. 22, 1978, now U.S. Pat. No. 4,257,701, issued Mar. 24, 1981, whichis a division of application Ser. No. 850,348, filed Nov. 10, 1977, nowU.S. Pat. No. 4,122,462, issued Oct. 24, 1978, which is a continuationof application Ser. No. 611,783, filed Sept. 9, 1975, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an image information recording apparatus, inwhich a light beam is modulated by an extraneous signal to form aninformation pattern, and this information pattern is recorded on arecording medium. More particularly, it relates to an image informationrecording apparatus for recording a plurality of different types ofinformation from different information sources on a recording medium ina superposed relationship.

The present invention will thus be effective in modulating light beamssuch as laser light, etc. (hereinafter referred to simply as a first anda second light beam, although they may be more than two beams) bycharacter or pattern information (first information) signal fromm anelectronic computer, etc. so as to be rendered into an image informationpattern, and in recording another image information pattern such as arecord format the (second information) pattern being different from thefirst information pattern and simultaneously overlayed on the firstinformation pattern.

2. Description of the Prior Art

Necessity often arises for recording information from an electroniccomputer, etc. in accordance with a prescribed format. In such cases, ithas heretofore been the practice to pre-print sheets of recording paperwith that format and record the output information from the computer,etc. on these pre-printed recording sheets. Such a conventional method,however, has involved the necessity for pre-printing the recordingsheets with the format which may include character frame, ruled lines,ornamental patterns, fixed character information, etc., and, onceprinted, the format could not easily be altered. Further, selection of aformat suited for the content of an information pattern has involved thecumbersome procedure of exchanging the recording paper pre-printed witha desired format. When a unit electronic computer is used for multiplepurposes to obtain various types of output information, it isinconvenient from the stand point of high-speed printing of theinformation that recording sheets having a different format for eachtype of information pattern should be changed.

SUMMARY OF THE INVENTION

It is an object of the present invention to eliminate all theabove-noted disadvantages peculiar to the prior art, and to provide sucha recording apparatus as will hereinafter be described for recording aplurality of different kinds of information from different informationsources by the use of a plurality of light beams such as laser light,etc.

That is, the present invention provides an apparatus, in which a lightbeam is modulated by an information signal and recorded on a sensitiverecording medium, and in which, for recording a plurality of differentkinds of information from different information sources, there isformed, for example, first and second light beams, of which the secondlight beam is made into a signal by a second information source, andsuch signal is synthesized with a signal from a first information sourceto modulate the first light beam, thereafter the synthesized signal isused to modulate the first light beam and, the thus modulated imageinformation is recorded on the recording medium.

It is also an object of the present invention to provide an apparatusfor recording image information from a plurality of differentinformation sources, and which comprises first and second informationsources, first and second light beam forming means, means for deflectingthe first and the second light beams in synchronism with each other,means for modulating the first light beam by a signal from the firstinformation source, means corresponding to the second information sourceand for generating a signal in response to the input of the deflectedsecond light beam means for synthesizing such signal and a signal fromthe first information source, and means for recording the first lightbeam after the modulator, whereby the first and the second informationpattern may be recorded in an overlaid manner.

It is another object of the present invention to provide an imageinformation recording apparatus, wherein, by the use of optical overlaymeans, any format can be easily recorded simultaneously with theinformation recording, and the exchange of the format can be done simplyand quickly by causing a drum carrying thereon a plurality of formatsaxially slidable with respect to each other, or by interchanging theformat drum, or by replacement of the master paper or master film forthe format. If a polarisation beam splitter is used for such opticaloverlay, the transmission factor of the laser beam can be improved, sothat the recording speed may become higher than in the case when aconventional beam splitter is used, and the use of a light beamoscillator such as a low output beam oscillator, etc. becomes possible.

It is a further object of the present invention to provide an imageinformation recording apparatus, wherein a laser beam is deflected andmodulated by an output information from an electronic computer, and theinformation is image-formed on a sensitive recording medium, while, atthe same time, an image reflected by or transmitted through a masterfilm or the like providing a desired format is optically synthesizedwith the abovementioned laser beam and subjected to light exposure,whereby the two kinds of image information may be recorded at a highspeed to provide a hard copy of high quality with the aid of a suitableoptical recording means, for example, the electrophotographic process asdisclosed in Japanese Patent Publication No. 23910/1967 corresponding toU.S. Pat. No. 3,666,363.

According to one aspect of the present invention, there is provided animage information recording apparatus, in which a light beam ismodulated by an information signal to effect recording of the imageinformation on a recording medium, and which comprises light beamforming means, means for modulating the light beam from the light beamforming means in accordance with the image information, image-forminglens means for focussing the light beam from the modulator means on therecording medium, means for synthesizing the recording medium, means forcausing the modulated light beam to scan over the recording medium, andmeans for overlaying the abovementioned image information and otherimage information with respect to the recording medium.

According to another aspect of the present invention, there is providedan image information recording apparatus, in which a light beam ismodulated by an information signal to effect recording of the imageinformation on a recording medium, and which comprises first and secondlight beam forming means including a beam splitter for splitting thelight beam or beams from one or two laser oscillators, modulator meanscapable of modulating the light beam from the first light beam formingmeans in accordance with a first image information signal, means fordeflecting the first and second light beams in synchronism with eachother, a second image information carrier to be scanned by the secondlight beam deflected by the deflector means, means for overlaying thesignal from the second image information source upon the the first imageinformation pattern, and image-forming lens means for focussing upon therecording medium the first light beam modulated in the modulator meansby the signal from the overlay means.

According to a further aspect of the present invention there is providedan image information recording apparatus, wherein a primary electriccharging is carried out upon the surface of an insulating layer of anelectrophotographic sensitive medium consisting essentially of anelectrically conductive substrate, a photoconductive layer, and anelectrically insulative layer, then a first light image of a laser beamdeflected and modulated by an extraneous signal is caused to scan overthe insulating layer for exposure, and simultaneously with, or prior to,or subsequent to the scanning, AC corona discharge, or secondary coronadischarge having an opposite polarity to that of the primary charge isapplied to the insulating layer, and further a second light imageexposure is effected in synchronism with the first light image exposureposition to form an electrostatic latent image of a synthesized image.

The foregoing objects and other objects as well as the detailedconstruction and operations of the present invention will become morefully apparent from the following detailed description of the preferredembodiments of the invention taken in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a top plan view illustrating the construction of an embodimentaccording to the present invention;

FIG. 3 is a side view thereof;

FIG. 3 is a perspective view of the embodiment shown in FIG. 1;

FIG. 4 is a perspective view showing a modified form of the secondaryimage projecting means of FIGS. 1 and 2;

FIG. 5 illustrates one example of the electrophotographic process foruse with the apparatus of the present invention;

FIG. 6 is a perspective view showing the construction of the imageinformation recording apparatus according to another embodiment of thepresent invention;

FIGS. 7(A) to (D) are respectively circuit diagrams showing variousforms of the modulated signal synthesizing means applicable to theapparatus of the present invention;

FIG. 8 is a perspective view showing the construction of the apparatusaccording to still another embodiment of the present invention;

FIG. 9 is a schematic block diagram corresponding to and representativeof the secondary image projecting means shown in FIG. 4;

FIG. 10 illustrates a modification of an essential part of theconstruction shown in FIG. 9;

FIG. 11 is a block diagram of another modification of the essential partof the construction shown in FIG. 9;

FIG. 12 is a perspective view of a further embodiment of the presentinvention;

FIG. 13 shows a perspective view of the driving mechanism for the secondlight image in the FIG. 12 embodiment;

FIG. 14 is a circuit diagram of the means for synchronizing the firstand the second light image in the FIG. 12 embodiment;

FIG. 15 is a time chart for the synchronizing means shown in FIG. 14;

FIGS. 16(a) through 16(i) inclusive illustrate the electrophotographicprocess;

FIGS. 17(a) through 17(d) illustrate samples of images formed by theapparatus of the present invention;

FIG. 18 is a perspective view showing still further embodiment of thepresent invention;

FIG. 19 is a cross-sectional side elevation of the FIG. 18 embodiment;

FIGS. 20(a) through 22(d) inclusive show various forms of the first andthe second exposed images as synthesized;

FIG. 23 shows a block diagram of an arrangement for controlling theimage synthesis shown in FIGS. 20(a) through 22(d);

FIGS. 24 and 25 are respectively perspective view and cross-sectionalside elevational view showing another embodiment of the presentinvention; and

FIGS. 26(a) through 28(d) inclusive show various forms of the imagesynthesis in the first exposure.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Several preferred embodiments of the present invention will hereinafterbe described in detail with reference to the drawings.

FIGS. 1 and 2 diagrammatically show a basic construction according to anembodiment of the present invention. A laser beam oscillated from alaser oscillator 1 is introduced into the input opening of a modulator 3by reflection mirrors 2. The mirrors 2 are inserted to bend the lightpath to minimize the space occupied by the apparatus, and may beeliminated if they are not necessary. The modulator 3 may be either anacousto-optic modulator element utilizing the well-known acousto-opticeffect, or an electro-optic element utilizing the electro-optic effect.In the modulator 3, the laser beam undergoes weak or strong modulationin accordance with an input signal to the modulator such as, forexample, an output signal from an electronic computer, etc.

If the laser oscillator is a semiconductor laser, or even in the case ofa gas laser, of an internal modulation type laser of a class whereincurrent modulation is possible, or of a class wherein a modulatorelement is incorporated in the oscillated light path, the modulator 3may be emitted, and the laser beam is introduced directly into a beamexpander 4.

The laser beam from the modulator 3 has its beam diameter enlarged bythe beam expander 4 while it remains to be a parallel beam. The laserbeam with its beam diameter having been enlarged is projected onto arotary polygonal mirror 5 having a plurality of mirror surfaces. Therotatory polygonal mirror 5 is mounted on a shaft provided with a highprecision bearing such as, for example, a pneumatic bearing, and drivenby a constant speed drive meter 6 such as, for example, an hysteresissynchronous motor or DC servomotor. The laser beam 12 which ishorizontally swept by the rotatory polygonal mirror 5 is focussed as aspot on a photosensitive drum 8 by an image-forming lens 7 having an f-θcharacteristic to be explained hereinafter. In ordinary image-forminglenses, there exists a relationship to be represented by the followingequation with respect to the position r, at which an image is formed onthe image plane when the incident angle of light is taken as θ:

    r=f· tan θ                                  (1)

where: f is the focal length of the image-forming lens. The laser beam12 reflected by a predetermined rotational polygonal mirror 5 as in thepresent embodiment changes its incident angle onto the image-forminglens 7 as a linear function with lapse of time. Thus, the moving speedof the spot position focussed on the photosensitive drum 8 acting as theimage plane is non-linearly varied and therefore not constant. In otherwords, the moving speed of the spot increases where the angle ofincidence becomes greater. Therefore, when a train of spots are depictedon the photosensitive drum 8 with the laser beam being "ON" at apredetermined time interval, the space intervals between adjacent spotswill be greater at either end of the train than at the center thereof.To avoid such a phenomenon, the image-forming lens 7 is designed to havethe following characteristics:

    r=f·θ                                       (2)

Such image-forming lens 7 will hereinafter be referred to as "f-θ lens".When the parallel light beam is focussed in the form of a spot by theimage-forming lens, the minimum diameter d_(min) of the spot is givenas:

    d.sub.min =f(λ/A)                                   (3),

where: f is a focal length of the image-forming lens; λ the wavelengthof the light used; and A the incident aperture of the image-forminglens. Thus, when f and λ are constant, the minimum diameter d_(min) willbe smaller as A becomes larger. The aforementioned beam expander 4 isused to assure such an effect. This means that this beam expander 4 maybe omitted, if the minimum necessary spot diameter d_(min) is obtainedby the beam diameter of the laser oscillator. A beam detector 18comprises a small incidence slit and a photoelectric converter element(for example, a PIN diode) having a quick response time. The beamdetector 18 serves to detect the position of the laser beam 12 to beswept, and, with this detected signal determines the timing for start ofan input signal to the modulator 3 which is to impart a desired lightinformation pattern onto the photosensitive drum. Thus, the error in thesplitting accuracy of each reflecting surface of the rotary polygonalmirror 5 and the irregularity in synchronization of horizontal signalsresulting from irregular rotation of the mirror may be greatly reducedto ensure good quality of the resulting image as well as to permit awider tolerance of precision required of the rotary polygonal mirror 5and the drive motor 6, which in turn leads to lower cost of manufacture.

The laser beam 12, deflected and modulated in the above-describedmanner, is irradiated on the photosensitive drum 8 to form thereon anelectrostatic latent image, and then developed into a visible imagethrough an electrophotographic process, after which the visible image istransferred onto a recording paper of ordinary quality and thetransferred image is fixed and delivered as a hard copy as will beexplained hereinafter.

Disposed between the f-θ lens 7 and the photosensitive drum 8 is apolarization beam splitter 14 which is the characteristic feature of thepresent invention. The beam splitter 14 is provided to synthesize animage reflected by the polygonal mirror 5 and another image obtainedfrom a format drum 16. The construction of the format drum 16 will nowbe explained by reference to FIG. 2.

The format drum 16 has webs of master paper 20 wound around it, each webbeing arranged contiguously in the axial direction of the drum. Thesewebs of master paper 20 have several kinds of format depicted thereon.By axially moving this format drum 16, any desired format can beselected. From the web of master paper 20 having the selected format,information from this master paper 20 can be directed as a reflectedlight image toward the image-forming lens 15 by the reflection method,namely, by irradiating a light beam from a light source 17 (such asfluorescent lamp, halogen lamp, etc) on the master paper 20 through aslit 19. The light passed through the image-forming lens 15 is overlaidupon the laser light by the polarization beam splitter 14 disposed neara location where the horizontal expansion of the beam width in thehorizontal direction is as narrow as possible, whereby the light beam isimage-formed on the photosensitive drum 8 either in the same size as theoriginal image, or in an enlarged or a reduced size. The light enteringinto the polarization beam splitter 14 is usually unpolarized, hence, inprinciple, the information is forwarded to the photosensitive drum 8with an efficiency of 50%. By rotating this format drum 16 insynchronism with rotation of the photosensitive drum 8, the informationin the master format paper 20 is completely delivered to thephotosensitive drum 8. Such synchronization is accomplished in thefollowing manner. As shown in FIG. 3, the light emitted from a lamp 21passes through a hole 25 perforated in the side walls of thephotosensitive drum 8 and is detected by a detector 22 as a startsignal. By a control circit 23 using this start signal as a triggersignal, a pulse motor 24 is driven to rotate the format drum 16 insynchronism with the photosensitive drum 8.

Since the format paper is attached to the format drum 16 as describedabove, the format information may be freely changed as by replacement ofthe format paper or the format drum. Also, the format paper may bewritten in a negative or positive form depending on necessity. In thismanner, the data and the format are irradiated on the photosensitivedrum at the same time, after which the formed electrostatic image isdeveloped into a visible image by an electrophotographic process asdisclosed in, for example, Japanese Patent Publication No. 23910/1967corresponding to U.S. Pat. No. 3,666,363, and then the developed imageis transferred onto a recording paper of ordinary equality and deliveredas a hard copy.

By the afore-described procedures, the information from an electroniccomputer, etc. may be recorded, while, at the same time, a desiredformat may be printed.

One example of the electrophotographic process applicable to the presentembodiment will be explained by reference to FIG. 5 which illustratesthe process disclosed in Japanese Patent Publication No. 23910/1967. Thesurface of an insulating layer of the photosensitive plate 8 basicallycomprising an electrically conductive substrate, a photoconductivelayer, and an insulating layer is uniformly charged in advance to thepositive or the negative polarity by a first corona charger 9 to captureelectric charges having an opposite polarity to the pre-charge in theinterface between the photoconductive layer and the insulating layer, orin the interior of the photoconductive layer. Subsequently, a compositelight beam consisting of a first image by the laser light 12 and asecond image 29 by the format information is irradiated on the surfaceof the insulating layer to be charged, while, at the same time, ACcorona discharge from an AC corona discharger 10 is applied to the sameinsulating layer surface to form on such surface a pattern resultingfrom the potential difference created in accordance with the light anddark patterns of the light beam. Then, the entire insulating layersurface is subjected to uniform overall exposure to form thereon anelectrostatic image having high contrast. After the overall exposure,the electrostatic image is developed into a visible image by adeveloping device 13 with the aid of a developer chiefly composed ofcharged toner particles. A further corona discharger 75 is then used toremove excess developer and thereafter the visible image is transferredonto paper or other appropriate transfer medium 11 by the use of anothercorona discharger 76 followed by fixation of the transferred image byfixing means 46 utilizing an infrared ray lamp, a hot plate, or else toprovide a printed electrophotographic image. On the other hand, afterthe image transfer, the insulating layer surface is cleaned by acleaning device 48 to remove any residual charged particles therefrom tomake the photosensitive drum 8 ready for reuse.

The photosensitive drum usable with the present invention is notrestricted to the one disclosed in the above-mentioned Japanese PatentPublication No. 23910/1967 corresponding to U.S. Pat. No. 3,666,363, butother electrophotographic methods, silver salt recording method or anyother recording method may equally be adopted. Further, the means fordeflecting the laser beam is not restricted to the rotatory polygonalmirror 5, but a well-known acousto-optic or electro-optic deflectorelement or a galvanometer mirror may also be used.

The polarization beam splitter 14 will now be described. This beamsplitter has the property that, of the light beam directed thereonbecomes P-polarized (a polarized light whose plane of polarization isparallel to the plane of the drawing sheet of FIG. 2) which istransmitted completely therethrough, while it causes S-polarization (apolarized light whose plane of polarization is normal to the plane ofthe drawing sheet of FIG. 2) to be completely reflected.

Now assume that the polarization beam splitter 14 causes the P-polarizedlight to pass therethrough, and that the output light from the laseroscillator 1 is the P-polarized. In this case, the incident light canreach the photosensitive drum with the aid of the polarization beamsplitter 14 without any energy loss which would be caused by aconventional beam splitter. Actually, however, light is more or lessreflected because even in a laser oscillator provided with a Brewsterwindow, the degree of polarization is not perfect and because thepolarized light is offset to some extent by the modulator, the beamexpander, the reflection mirror, etc. Further assume that the incidentlaser beam is either S-polarized or circular polarization with thepolarization beam splitter 14 being in the above-described condition. Inthis case, a 1/2 or a 1/4 or a 3/4 wavelength plate is placed at 4' (seeFIGS. 1 and 3) between the beam expander 4 and the rotatory polygonalmirror 5 to convert the laser beam into P-polarized beam. Such waveformplate may be replaced by other means capable of changing the directionof polarization such as, for example, a combination of a 1/4 wavelengthplate and a polarizing plate. Also, the plate of installation may be anypoint between the laser oscillator and the polarization beam splitter.By doing so, the polarization beam splitter 14 may effectively actagainst energy loss as in the aforementioned case.

In the above-described condition of the polarization beam splitter, whenthe incident laser beam has no polarization, the choice of thepolarization beam splitter or the conventional beam splitter may bedetermined by the difference in the energy loss between them. This alsoholds true even if the polarization beam splitter is of the type whichcauses S-polarized light to pass therethrough.

The use of such a polarization beam splitter 14 in the optical synthesisof the information from an electronic computer and the information fromthe format master paper 20 is highly advantageous from the standpoint ofenergy loss. More specifically, it becomes possible to record theinformation at high speed by the use of a laser oscillator having thesame output capacity, or to miniaturize the entire apparatus by use of alaser oscillator of a smaller size. It is also possible in the presentembodiment to reverse the locations of the f-θ lens 7 and thepolarization beam splitter 14. In that case, the image-forming lens 15may be substituted for the f-θ lens 7, or for a combination of asuitable auxiliary lens and the f-θ lens 7. (If it is not desired thatthe image on the master paper be inverted on the photosensitive drum, asuitable lens, in addition to the image forming lens 15, is placedbetween the master paper and the photosensitive drum so as to cause theimage of the master paper and the image on the photosensitive drum to beon the same direction.)

Of the methods for obtaining the format information from the format drumin the form of a light signal, there is a transmission method which willbe explained hereinbelow, besides the reflection method as described inthe foregoing embodiment. This transmission method will now be describedin reference to FIG. 4. The light emitted from a light source 27(fluorescent lamp, halogen lamp, etc.) disposed within the format drum16 passes through a slit 28 to illuminate a master film 26 wound aroundthe format drum 16, from which the format information is emitted as alight signal toward the image forming lens 15. The subsequent processes,wherein such light signal is synthesized with the laser light image toform an electrostatic image on the photosensitive drum, are the same asdescribed with respect to the previous embodiment. Interchange of theformat is also similar to that in the previous embodiment, wherein thewebs of the master format paper 20 are used.

The present invention is of course not restricted to the above-describedembodiments, but covers various modifications without departing from thescope of the invention as defined in the appended claims.

It will be appreciated that, in the laser device of the presentinvention which includes means for deflecting and modulating the laserlight by an extraneous signal input such as the output signal from anelectronic computer, etc., and means for recording the deflected andmodulated laser light on a sensitive medium such as a photosensitivedrum, etc., there is provided means for focussing on the same imageplane of the laser light recording means a second image such as, forexample, an image providing a format, which is different from the laserlight (a first image), so that the second image may be recorded alongwith the first image due to the laser light and thus, any desired formatmay be recorded freely and independently of the output device for thelaser light image in overlaid relationship with the laser light image.Moreover, selection of the format can be accomplished very simply, and acomposite image consisting of dual images can be advantageously obtainedsimultaneously on one and the same recording surface by the opticaloverlay technique. Consequently, the heretofore required procedure ofpre-printing the secondary image such as prescribed formats, etc. on thelaser light image recording paper can be omitted. In addition, suchoptical overlay is advantageous in that if a plurality of secondaryimage projecting means are installed, the laser light image as theprimary image and a plurality of images such as secondary, tertiary andsubsequent images may be recorded at the same time in an overlaidrelationship on one and the same recording surface, whereby recordingdensity of the information on one and the same recording papereffectively and remarkably increases.

The invention has been shown with respect to the embodiments, whereinoutput information from an electronic computer, etc. is converted intolaser light. In these embodiments, the light to be used is notrestricted to laser light, but any polarized light beam may attain thesame objects, function and resulting effect of the present invention.

Still another embodiment of the present invention will now be describedin detail with reference to FIG. 6 which schematically shows the basicconstruction of this embodiment and similar components will retain thenumerical designations used in the previous embodiments.

The laser beam oscillated from a laser oscillator 1 is introduced intothe input opening of a modulator 3 by reflection mirrors 2. In themodulator 3, the laser beam undergoes weak or strong modulation inaccordance with the input signal to the modulator. The laser beam fromthe modulator 3 has its beam diameter enlarged by a beam expander 4while it remains a parallel beam. The laser beam with its beam diameterhaving been expanded is projected onto a rotatory polygonal mirror 5having a plurality of mirror surfaces. The rotatory polygonal mirror 5is mounted on a shaft supported by a high precision bearing, and drivenby a constant speed motor 6. The laser beam 12 to be horizontally sweptby the rotational polygonal mirror 5 is focussed on a photosensitivedrum 8 as a spot through an image-forming lens 7 having theabove-described f-θ characteristic.

The laser beam so deflected and modulated is irradiated on thephotosensitive drum 8, and the formed image is developed into a visibleimage through an electrophotographic process, after which the developedimage is transferred and fixed onto recording paper of an ordinaryquality and delivered as hard copy.

In FIG. 6, a half-mirror 30 reflects a part of the laser light before itenters into the modulator 3 to form a second light path (the laser lighttraveling along the second light path will hereinafter be referred to asthe "second laser light beam" and be distinguished from "the first laserlight beam" which passes through the modulator 3.

The reason for forming the second laser light beam 41 is to enable aplurality of information patterns from different information sources tobe recorded on one and the same recording medium. In the shownembodiment, the second laser light beam 41 is used to produce a secondinformation signal, i.e., a read-out light for the image informationsuch as format, and so on. By applying the laser light to this imageinformation, photoelectric conversion in effected to produce anelectrical signal corresponding to the image information. As thesensitivity of the photoelectric converter of this type is generallyhigher than that of the photosensitive medium for the order of 10³ to10⁶ times, the ratio of dividing the initial laser light into the firstlaser light beam 40 and the second laser light beam 41 by thehalf-mirror 30 may be 1:10³ -10⁶ for the second laser light, when theinitial laser light before it is split is taken as 1. This means thatthe second laser light may be very small in intensity for the splitting,hence the half-mirror 30 may be substituted with a transparent glassplate, as the case may be.

The second laser beam is given its particular light path so as to beprojected onto one of the reflecting surfaces of the rotatory polygonalmirror 5 through a beam expander 32, similar to the beam expander 4. Thelight beam reflected by the reflecting surface is then converged by alens 33 to be focussed on a predetermined format 35 which is a secondinformation carrier. A galvanometer mirror 34 disposed between the lens33 and the format 35 is of a known type, and acts to deflect the secondlaser beam to the format 35.

As the first laser light beam 40 has been modulated by an informationsignal (to be described hereinafter) applied to the modulator 3, and hasbeen projected on the rotatory polygonal mirror 5 through the beamexpander 4, as has already been described, the first and the secondlaser light beams, even if they are not projected on one and the sameincident surface, are perfectly deflected in synchronism with eachother, because both laser light beams are reflected by the samerotational polygonal mirror. On account of this, the deflecting speedand synchronization are perfectly coincided between the first laserlight beam which is the recording light and the second laser light beamwhich is the reading light. Accordingly, in FIG. 6, the recordingposition on the photosensitive medium 8 in the horizontal direction andthe recording position on the predetermined format 35 coincide with eachother. Since the photosensitive medium 8 is constructed in the form of adrum and rotates, the vertical movement of the light beam on the format35 must occur in synchronism with the rotation of the drum. In thepresent embodiment, this is realized by the use of the galvanometermirror 34. That is, the mirror 34 is driven by a saw-tooth wave currentcorresponding to the rotation of the drum 8. Alternatively, it may bepossible that the format 35 is vertically moved by a method for movingthe light beam in the vertical direction in synchronism with therotation of the drum. In the illustrated embodiment, the format 35 isconstructed with a format film for transmitting light therethrough,although any other information carrier may be used when reflected lightis utilized.

The light transmitted through the format film is converted into anelectrical signal by a photoelectric converter 36 such as aphotoelectric mutiplier tube, etc. Such electrical signal is applied toone of the input terminals of an electrical signal synthesizingamplifier 37 as a signal B corresponding to the format surface which isthe second information source. A first information signal A which is theoutput information from an electric computer, etc. is applied to theother input terminal of the amplifier 37 in which the signal issynthesized. After the synthesis, the signal is fed from the amplifierand applied to the modulator 3 as an input signal. By this input signal,the first laser light is modulated and projected, for recording, ontothe photosensitive drum 8 as light information the first and the secondinformation sources being overlaid, as previously described.

The manner of the synthesis within the synthesizing amplifier 17 isvariable, and typical examples thereof will be explained in reference toFIGS. 7(A)-7(D). FIG. 7(A) shows an example in which the additionoperation is carried out with an output signal A from the electroniccomputer, etc. and on operational amplifier 50 with a signal B obtainedfrom the format remained to be an analog signal. According to thisexample, tone of the format is recorded simultaneously with the signal Ain high fidelity.

FIG. 7(B) shows an example, in which the density of the signal B, inparticular, on the recording surface, is made constant by converting theanalog signal B into a binary signal consisting of 0 and 1 through acomparator 51, and by causing an output resulted from the logical sum ofthe binary signal information from a computer, etc. and an OR gate 52 tobe applied to the modulator.

FIG. 7(C) shows an example, in which the analog signal B is convertedinto a binary signal by the comparator 51 as previously described,thereafter its gain is dropped by an attenuator 53 to a level lower thanthe image signal A from a computer, etc., and then the low-levelledanalog signal is applied to the operation amplifier 50. By so doing, thedensity of the format on the recording surface becomes low.

In a further example shown in FIG. 7(D), the signal B is converted intoa binary signal by a comparator 51, is inverted by an inverter 54, afterwhich the inverted signal is applied to an operational amplifier 50together with the signal A so that the tone of the format on therecording surface may be inverted. By so doing there can be provided anegative or a positive image which is an inverted format image.

FIGS. 8 and 9 illustrate other embodiments of the present invention.

In the above-described embodiments, when the first and the second laserlight beams are projected onto different reflecting surfaces of therotational polygonal mirror 5, errors in finished precision on eachreflecting surface of the rotational polygonal mirror would result isvertical irregularity of the image corresponding to the format image onthe photosensitive drum. In other words, during the recording, theperiod of time, at which the spot of laser light comes to a particularhorizontal position on the drum, slightly deviates due to errors inprecision of the mirror surfaces of the rotary polygonal mirror,irregular rotation of the driving motor, and other factors. If a beamposition detector 18 is used to correct this deviation, the relativehorizontal position of the laser light on the recording drum and on theformat will become deviated for each scanning line. To overcome thisproblem, it is preferable that the first and the second laser lightbeams are projected on one and the same mirror surface of the rotarypolygonal mirror 5.

In view of the abovementioned point, it is further preferable to use acommon image-forming optical system, by which it will also becomepossible to eliminate any distortion or positional deviation which wouldotherwise result from the use of different image-forming systems. Also,if the magnification of the image forming system concerned with theformat information is reduced, microfilm or the like may become usableas the format, which facilitates interchange and retrieval of theformat. Such arrangement is advantageous when a number of formats are tobe automatically interchanged.

The specific construction of the above-described embodiment is shown inFIGS. 8 and 9. In explaining the embodiment, those elements which arecommon to the above-described embodiment are designated by the samereference numerals, and the description thereof is omitted or otherwisemade brief.

The second laser light beam 41 is produced by using a half-mirror 30 tosplit the beam. The beam 41 is then reflected by a mirror 31 to passthrough a beam expander 32, and is projected onto a mirror surface 5a onwhich the first laser light is also projected (see FIG. 9).

The laser light beams reflected by the mirror surface 5a pass through acommon image-forming lens (f-θ lens), after which the first laser lightbeam 40 is projected upon the recording surface of the photosensitivedrum 8, while the second laser light beam 41 is reflected by a mirror 60so as to be projected and focussed upon a second information carrier 35'such as a format, and so on. The amount of the reflected light varies inaccordance with the information formed on the carrier 35'. Suchreflected light passes through a suitable optical system (not shown) toa photoelectric converter 36' where it is converted into an electricalsignal. The electrical signal resulting from the conversion is appliedto a synthesizing amplifier 37' as the second information signal B, andsynthesized with the first information signal A which is the recordinginformation and, as is the case with the abovementioned embodiment,thereafter the synthesized output signal is applied to the modulator 3to modulate the first laser light beam. The first laser light beam somodulated is projected into the photosensitive drum 8 via the rotatorymirror 5 and through the image forming lens 7 to effect recording of theinformation thereon, as already noted. In this embodiment, the secondinformation carrier 35' is moved by a conventional driving means insynchronism with rotation of the photosensitive drum 8 and in thedirection perpendicular to the scanning direction of the mirror 5.

FIG. 10 illustrates a modification of the foregoing embodiment. In thismodified embodiment the first laser light beam 40 and the second laserlight beam 41 are projected onto a mirror surface at a common pointthereon and are reflected therefrom so as to reduce the requisitethickness of the rotational mirror shown in FIG. 9. For this reason,this figure is depicted in an exaggerated manner, although, in reality,the light paths are so set that the two laser light beams may beincident upon the thin rotational polygonal mirror 5' at slightlydifferent angles of incidence. Since the angles of reflection of themirror surface are also variable with the angles of incidence, the lightbeams can be separated, so that the second laser light beam is made tobe reflected toward the second information carrier 35' by the mirror 60.The other component elements in this modification are similar to thosein the foregoing embodiment. This modification is advantageous in thatthe thickness of the rotational polygonal mirror can be very small asalready mentioned.

FIG. 11 shows, in block diagram, another modification of the previousembodiment, wherein those component elements which are similar to thosein the previous embodiment are given similar reference numerals.Assuming that the first laser light beam for recording the outputinformation from an electronic computer is P-polarized (polarized lightwhose plane of polarization is parallel to the plane of the drawingsheet of FIG. 11), this laser light is split into a first and a secondlight beams by a half-mirror 30, and the second laser light beam isdirected by a mirror 31 to a phase plate 80 disposed in the second lightpath and converted into the S-polarized light (polarized light whoseplane of polarization is normal to the plane of the drawing sheet ofFIG. 11), and the S-polarization in turn is reflected by a mirror 66, tobe directed to a polarization half-mirror 67 disposed in the first lightpath where it is synthesized with the first laser light beam. Thispolarization half-mirror 67 has a property of permitting passagetherethrough of the first laser light (P-polarization), and reflectingthe second laser light (S-polarization). The synthesized light passesthrough a beam expander 4 to project onto a rotatory polygonal mirror 5'from which it pass through an f-θ lens 7 to another reflection mirror 68where the second laser light is again separated from the first laserlight, and projected toward a second information carrier 35'. The lighttransmitted through or reflected by this information carrier isphotoelectrically converted to provide a second information signal B,which is then synthesized with the output information signal A from anelectronic computer, etc., and the synthesized signal is used tomodulate the laser light in the modulator 3, as already described inconnection with the foregoing embodiments. Recording of the laser lightafter the modulation may be effected in exactly the same manner as inthe above-described embodiments.

In the above embodiment, the present invention has been described withreference to recording information from two independent informationsources on a common recording medium, but it will be apparent thatinformation from more than two sources can be synthesized and recordedaccording to the present invention in exactly the same manner asdescribed in the foregoing.

According to the present invention, as has so far been described, aplurality of light beams are made to correspond in number to theinformation sources, and, when one of the light beams is modulated by asignal from the corresponding information source, the other informationis read out by other light beams, and the signal so read out is added tothe modulating signal to form a synthesized modulating signal, withwhich at least one light beam is ultimately modulated, thereafter thelight beam is projected upon a photosensitive medium to effect therecording. Thus, the present invention can eliminate the heretoforerequired procedures of recording a plurality of information patterns ona common recording medium through separate processes, and moreover,enables different types of information from various information sourcesto be recorded at one time as light information on the recording mediumby the same process, irrespective of the type of information to berecorded. As a result, the working efficiency and the recording densityadvantageously improve.

Still another embodiment of the present invention will now be describedin detail in reference to FIG. 12 which shows a perspective view of suchembodiment and wherein those component elements which are similar tothose of the previous embodiments are given similar reference numerals.

In FIG. 12, the laser beam oscillated from a laser oscillator 1 isdirected by mirrors 2 to the input opening of a modulator 3. The laserbeam from the modulator has its beam diameter enlarged by a beamexpander 4, while remaining a parallel light beam. The laser beam withincreased beam diameter is projected onto a rotary polygonal mirror 5having one or more mirror surfaces. The rotatory polygonal mirror 5 ismounted on a shaft supported by high precision bearings, and driven by aconstant speed motor 6. The laser beam 12 horizontally swept by therotatory polygonal mirror 5 passes through an image-forming lens 7having the above described f-θ characteristic, and is focussed as a spoton a photosensitive drum 8.

Exposure to a second light image such as a finite format, etc. will nowbe described in reference to FIG. 5. An original image informationsurface such as a predetermined format 35, etc. attached to a formatdrum 16 is illuminated by an exposure lamp 17 (fluorescent lamp, halogenlamp, etc.). The light-reflected by the original then passes through aslit means 19 and is reflected by a mirror 60 to further travel throughan image-forming lens 33 so as to be enlarged, reduced or kept in thesame size as the original and focussed as a format light beam 29 on thephotosensitive drum 8. Incidentally, this reflection mirror 60 is forreducing the space occupied by the apparatus, and may of course beeliminated if it is not required. The original image information surfaceor format 35, etc. need not always be of the reflection type, but may beof the transmission type such as film, etc., which bears thereon apositive image.

In the above-described manner, the data of the first light image and theformat of the second light image are synthesized on the photosensitivedrum 8.

The driving mechanism for the finite format in the present embodimentwill now be explained in detail in reference to FIG. 13. In FIG. 13,various kinds of predetermined format originals 35 are mounted side byside on the format drum 16 and rotated at a predetermined velocity by aformat driver 38. The formats are also moved with a format drumsupporting bed 42 in the axial direction of the format drum 16 by aformat selector 39 so that a particular format original 35 may beselected from among the various kinds of formats. Interchange of thepredetermined format originals 35 may be freely carried out byreplacement of the format paper or by replacement of the drum itself.

The format light 29 from the predetermined format original 35 isprojected upon a position synchronous with the position upon which thelaser beam 12 is projected. More specifically, when the format base drum16 rotating at a predetermined velocity arrives at a predeterminedrotational position, it produces a "ready" signal. After an adjustmenttime, data are entered and the projection of the laser beam starts. Thetime adjustment is such that, when the photosensitive drum is rotated tobring a portion thereof which has been exposed by the laser beam to anexposure position for exposure by the finite format light, the top ofthe page of the finite format original reaches that position.

The time difference T₂ between start of the data input and start of theexposure on the top page the finite format original is represented bythe following equation:

    T.sub.2 =(l.sub.l -f)/vpd

where l_(l) -f is the distance between the laser beam exposure positionand the finite format light exposure position; and vpd is the peripheralspeed of the photosensitive drum. Also, the time T₁ after the generationof the "ready" signal till exposure start for the page top of the finiteformat original is represented by the following equation:

    T.sub.1 =(l.sub.r -f)/vf

where l_(r) -f is the distance between the fitting position of the"ready" signal generating switch and the page top position of the finiteformat original; and vf is the peripheral speed of the finite formatoriginal. In the present embodiment, as shown in FIG. 13, the "ready"signal is generated by detecting a "ready" point 43 attached to one endof the format base drum 16 by a microswitch 44.

After reception of the "ready" signal, the start time is represented bya data start signal generated by a circuit shown in FIG. 14, i.e., bytriggering a monostable multivibrator with the "ready" signal, and mayeasily be adjusted by the inversion time of the monostable multivibratorthrough variation of its time constant.

This is shown in the time chart of FIG. 15. In this time chart the timeperiod from the reception of the "ready" signal till the data start,i.e., T₁ -T₂, is the inversion time of the monostable multivibrator andby adjustment of this time, the data input time is adjusted tosynchronize the page top of the finite format. In the presentembodiment, the finite format has been described as being of the drumtype. Alternatively, the finite format may of course be of the flattype.

Description will now be made of the printing portion 45 in FIG. 5. Theelectrophotographic process applicable to the present inventioncomprises various steps, as follows. That is, the surface of theinsulating layer of the electrophotosensitive medium 8, which mediumconsists essentially of an electrically conductive substrate, aphotoconductive layer, and an electrically insulative layer, isuniformly charged in advance to either positive or negative polarity bya primary corona charger 9 to capture electric charges of oppositepolarity to the primary charge existing in the interface between thephotoconductive layer and the insulative layer, or in the interior ofthe photoconductive layer. Subsequently, the laser beam 12 is irradiatedonto the surface of the charged insulative layer. Simultaneously with,prior to, or after, the laser beam irradiation the insulative layersurface is subjected to the AC corona discharge, or the secondarydischarge in opposite polarity to that of the primary charge by the useof a secondary corona discharger 10. Thereafter, the insulating layersurface is exposed to the positive image of the finite format light 29,by the light stimulus of which a surface potential difference is createdbetween the exposed portion of the photosensitive medium by the laserbeam as well as the dark portion corresponding to the finite format andthe remaining portion of the photosensitive medium to thereby form asynthesized electrostatic image. The thus obtained electrostatic imageis then developed into a visible image by developing means 13 using adeveloper composed chiefly of charged toner particles. Thereafter excesstoner is removed by a corona discharger 75 after which the visible imageis transferred onto paper or the like transfer medium 11 by theutilization of an internal or external field such as corona discharger76. Then, the transferred image is fixed by fixing means 46 such asinfrared ray lamp or hot plate to provide an electrophotographicallyprinted image 47. On the other hand, the insulating layer surface aftercompletion of the image transfer is cleaned by cleaning means 48 toremove any residual charged particles to make the photosensitive medium8 ready for reuse.

Formation and development of the synthesized latent image referred toabove will hereinafter be described in greater detail.

Referring to FIGS. 5 and 16, the surface of the insulating layer 46 ofthe photosensitive medium 55 is subjected to the uniform primary charge57 by a corona charger 9 (FIGS. 5 and 16a). This charge shouldpreferably be positive if the photoconductive layer 58 is formed of anN-type semiconductor, and negative if the layer 58 is formed of a P-typesemiconductor. In the shown example, the insulating layer surface ischarged to the positive polarity, and in correspondence to this positivecharge 57, charges 59 of the opposite polarity, namely, negativepolarity, are captured in the portion near the insulating layer 56 ofthe photoconductive layer 58.

Subsequently, the insulating layer surface is subjected to the AC coronadischarge 10 (FIGS. 5 and 16b), while, at the same time, it is beingsubjected to a first exposure A by the laser beam, the photoconductivelayer 58 in the bright area A_(L) of the photosensitive medium 55 isrendered electrically conductive by the light stimulus to be turned intoa state, wherein the captured charges 59 are proved to be dischargedtoward the electrically conductive substrate 61. Consequently, all or amajor part of the charges 57 on the insulating layer surface can beeasily removed along with the corresponding captured charges 59, inconjunction with the discharging action of the AC corona. In the darkarea A_(D), on the other hand, the resistance value of thephotoconductive layer 58 is so high that there is no discharge of thecaptured charges 59 toward the photoconductive substrate 61, under theinfluence of which the rate of discharging of the charges 57 on theinsulating layer surface by the AC corona is lower than in the brightarea A_(L). Nevertheless, there is little difference in surfacepotential (electrostatic contrast) between the two areas A_(L) andA_(D). Next, when a second exposure B by the finite format is effected(FIG. 16(c)), the charged state in the dark area B_(D) is maintained asit is, since there is no light stimulus in this area, hence no variationin the surface potential. Also, in the bright portion A_(L) of thebright area B_(L), which has been subjected to the first exposure,little variation takes place in the state of the photoconductive layer58 any longer, even if it is again exposed to light, and, accordingly,the surface potential of the insulative layer does not vary, so that itis maintained at a level substantially equal to that of the dark areaB_(D). In the bright area B_(L) other than the portions B_(D) and A_(L),the photoconductive layer 58 is, for the first time, rendered conductiveby the light stimulus, in consequence of which the captured charges 59are all discharged into the electrically conductive substrate 61,leaving therein only a quantity of the charges equivalent to the charges57 on the insulative layer surface and finally disappear. As the result,there occurs an abrupt increase in the external field within the charges57 on the insulative layer surface, the surface potential rises. Thus,there is created a great difference in the surface potential between thebright area A_(L) in the first exposure and the bright area B_(L) in thesecond exposure, whereby a latent image with high contrast is formed.The surface potential distribution on the photosensitive medium 55 atthis moment is shown in FIG. 16(d ). As seen, the surface potential ishigh (V_(D-L)) only in the portions which were dark in the firstexposure and became bright in the second exposure, and it issubstantially zero in the remaining portions.

Therefore, if such photosensitive medium 55 is developed with a toner,the synthesized image which has resulted from the first and the secondexposure may be made into a visible image.

FIG. 16(e) shows a case where the image development is carried out bythe use of a toner having an opposite polarity to that of the primarycharge, i.e., negative polarity. In this case, the toner particlesadhere to the area which was dark in the first exposure, but was brightin the second exposure. Inversion development, namely, the developmentusing the toner of the same polarity as that of the primary charge, canalso be effected, in which case the development is reverse to thepositive development. As is well-known, a much better result isobtained, if a developing electrode is employed.

In the above-described process steps, the AC corona discharge to beconducted simultaneously with the first exposure may be replaced by thecombined application of the first exposure and the secondary charge ofopposite polarity to that of the primary charge, and similar imagesynthesis can still be made.

When the secondary charge in opposite polarity to that of the primarycharge, i.e., the negative polarity is conducted to the photosensitivemedium 55 shown in FIG. 16(a), while it is being subjected to the firstexposure (see FIG. 16(f)) by the laser light, the photoconductive layer58 in the bright area A_(L) is rendered electrically conductive by thelight stimulus, and the captured charges 59 are brought to a state, inwhich they tend to be discharged into the conductive substrate 61. Inthis way, the primary charges 57 applied onto the surface of theinsulating layer are all discharged together with the correspondingcaptured charges 59 by the neutralizing action of the applied secondarycharges in opposite polarity to that of the primary charges.Subsequently, the charge polarity on the insulating layer surface isinverted by the applied secondary charges, and recharged to the negativepolarity as indicated by 45', in correspondence to which capturedcharges 57' of the positive polarity are produced.

On the other hand, in the dark area A_(D), the resistance value of thephotoconductive layer 58 is so high that there is no discharge of thecaptured charges 59, under the influence of which, all or a majorportion of the applied primary charges 57 on the insulating layer aredischarged only, but seldom is the dark area A_(D) re-charged to thenegative polarity as in the bright area A_(L). In this manner, thecharge distribution on the insulating layer surface in the bright anddark areas A_(L) and A_(D) is such that while the bright area A_(L) isof the negative polarity, the dark area A_(D) has no charge or haspositive charges, although there is little difference in the surfacepotential between the areas A_(L) and A_(D). In other words, since alarge quantity of the captured charges 59 which are of the same polarityas that of the charges applied on the surface of the insulating layer inthe bright area A_(L) remain in the dark area A_(D), and cause a strongexternal field, the surface potential is substantially equal between thebright area and the dark area, even if positive charges remain more orless on the surface of the insulating layer in the dark area A_(D). Whenthe second exposure B for the finite format image is subsequentlyconducted (FIG. 16(g)), the charged state in the dark area B_(D) remainsunchanged without any variation in the surface potential, because thereis no light stimulus imparted to this area. Also, in the portion of thebright area B_(L) which overlaps the bright area A_(L) in the firstexposure, the charges 57' in the photoconductive layer 58 no longerattenuate so much, even if the portion is again exposed to light,whereby a surface potential substantially equal to that of the dark areaB_(D) is maintained. On the other hand, as the remainder of the brightarea B_(L), exclusive of the areas B_(D) and A_(L) becomes electricallyconductive for the first time by the light stimulus, of the capturedcharges 59 are all discharged into the electrically conductive substrateand disappears, leaving a quantity of electric charges equivalent to theapplied positive charges 57 remaining on the insulating layer surface.As a result, the negative external field provided by the capturedcharges 59 abruptly attenuates and the surface potential of theinsulating layer increases. In case of the applied positive chargesstill remains on the insulating layer surface, the surface potential isinverted to a positive level, whereby there is created a largedifference in the surface potential between the areas B_(D) and A_(L)which maintain the negative surface potential, resulting in formation ofa latent image with high contrast. The surface potential of thephotosensitive medium at this time is as shown in FIG. 16(h), from whichit is recognized that the potential difference occurs between theportion which was dark in the first exposure, but bright in the secondexposure, and the remaining portion. When such latent image is developedby the use of toner having the same polarity as that of the primarycharge, the toner particles adhere to said remaining portion as shown inFIG. 16(i). When a toner having the opposite polarity to that of theprimary charge is used, development will occur in the reverse manner.

From the above-described electrophotographic process, it will beunderstood that, when the first exposure image by the laser beam asshown in FIG. 17(c) and the second exposure image by the finite formatas shown in FIG. 17(b) are synthesized, and the synthesized image isdeveloped by the use of a toner having the opposite polarity to that ofthe primary charge, it will represent a form as shown in FIG. 17(c), andthat, when the same synthesized image is developed by the use of a tonerof the same polarity as that of the primary charge, it will represent aform as shown in FIG. 17(d).

Specific examples of the synthesized image formation employed in theforegoing embodiment will be shown herein below.

A photosensitive plate comprising a photoconductive layer formed bycoating on an aluminum substrate of about 100-micron thickness aphotosensitive substance prepared by adding 10 grams of vinyl chlorideto 90 grams of copper-activated cadmium sulfide, and further adding andmixing a small amount of thinner to a thickness of 40 microns, and aninsulating layer of polyethylene terephthalate having a thickness of 25microns, was subjected to uniform primary charge at +1800 V by a coronadischarger, and then subjected to AC corona discharge simultaneous withexposure by an He-Ne laser at an exposure rate of 1 μj/cm², followed byexposure to the positive image of a finite format at an exposure rate of1 luxes/sec.. When this photosensitive plate was immediately immersedfor development in a positively charged toner, there appeared a veryclear synthesized positive image consisting of the laser image and thefinite format image.

As another example, a photosensitive medium was prepared byvacuum-evaporating on an aluminum substrate a Te layer to a thickness ofabout 1-micron, and further vacuum-evaporating on this Te layer an Selayer with 15% Te content to a thickness of about 50 microns to therebyform a photoconductive layer, and by subsequently applying to thesurface of the photoconductive layer a transparent insulative resin to athickness of about 30-micron, and setting the resin.

The surface of the insulative layer on this photosensitive medium wassubjected to uniform primary charge at -1000 V, and then subjected tosecondary charge at +1000 V simultaneous with exposure to an He-Cd laserat an exposure rate of 2 μj/cm², followed by exposure to the positiveimage at an exposure rate of 15 luxes/sec.. When this photosensitiveplate was developed by a magnetic brush using a negatively chargedtoner, a very clear, positive, synthesized image consisting of thenegative laser image and the positive format image was obtained. The useof a positively charged toner resulted in a very clear, negative,synthesized image.

In the following, a further embodiment of the apparatus according to thepresent invention will be described in detail by reference to FIG. 18showing a perspective view of this embodiment, and FIG. 19 showing sideelevational view thereof and wherein those components which are similarto those of previous embodiments are given similar reference numerals.

In FIGS. 18 and 19, the laser beam oscillated by a laser oscillator 1 isdirected by a mirror 2 to the input opening of a modulator 3. In themodulator 3, the laser beam is subjected to weak or strong modulation inaccordance with the input signal to the modulator, and then todeflection. The laser beam from the modulator 3 has its beam diameterenlarged by a beam expander 4, while it remains a parallel beam. Thelaser beam with its beam diameter so increased is projected upon arotational polygonal mirror 5 having a plurality of mirror surfaces. Therotational polygonal mirror 5 is mounted on a shaft supported by highprecision bearings, and driven by a constant speed motor 6. The laserbeam is horizontally scanned by the rotational polygonal mirror 5.Alternatively, the scanning may be effected by a galvanometer mirror notshown. The laser beam horizontally scanned by the rotational polygonalmirror 5 passes through an image-forming lens 7 having the abovedescribed f-θ characteristic, and is focussed onto photosensitive drum 8as a spot. A beam detector 18 comprises a small incidence slit and aphotoelectric converter element (for example, a PIN diode) having aquick response time. The beam detector 18 detects the position of thelaser beam to be swept, with which detection signal determines thetiming for the start of the horizontal scanning input signal to themodulator for imparting a desired light information pattern onto thephotosensitive drum. The reason for using the f-θ lens 7 and the beamdetector 18 has already been set forth in the foregoing.

The laser beam 12 modulated by an extraneous signal in theabove-described manner is projected upon the photosensitive drum 8 froma first exposure position which will be described later. On the otherhand, an original image surface such as a predetermined format 35 isplaced on a support 62 for the original image which is movable insynchronism with the laser exposure, and illuminated by an exposure lamp17 for the format 35. The thus illuminated original is reflected towardan original image forming lens 33 by a mirror 60. Thereafter, theoriginal image is directed to a second exposure position by mirrors 63and 64 so as to be projected on the photosensitive drum 8. Thus, thelaser image in the first exposure and the original image in the secondexposure are synthesized on the photosensitive drum 8.

Where there is no extraneous signal and the copying of an original imagealone is to be conducted, only the second exposure for the originalimage occurs, and no first exposure is carried out. On the other hand,where extraneous information alone is to be recorded, exposure of theoriginal image is omitted and, instead, overall irradiation of thephotosensitive drum 8 is carried out by means of an overall exposurelamp 65 at the second exposure position. Although, in the presentembodiment, the overall exposure lamp 65 has been provided foraccomplishing the overall irradiation, it may be done alternatively bycausing the light of the original exposure lamp to be reflected by areflecting surface provided on the original image support 62 at its restposition.

The printing section in FIGS. 18 and 19 will now be explained. Theelectrophotographic process applicable to the present invention is asfollows. That is, the surface of the insulative layer of theelectrophotosensitive drum 8 basically comprising an electricallyconductive substrate, a photoconductive layer, and an electricallyinsulative layer which is, in advance, subjected to uniform primarycharge in either the positive or the negative polarity by a first coronacharger 9 to capture charges in opposite polarity to that of the primarycharge at the interface between the photoconductive layer and theinsulating layer, or, in the interior of the photoconductive layer.Then, the laser beam 12 is irradiated onto the surface of the chargedinsulating layer. On the other hand, the insulating layer surface issubjected to AC corona discharge, or secondary discharge in oppositepolarity to that of the primary charge, by the use of a second coronadischarger 10, simultaneously with, or prior to, or, subsequent to, thelaser beam irradiation. Thereafter, the insulating layer surface isexposed to the positive image of the original image light 73, by thelight stimulus of which a surface potential difference is createdbetween the portion of the photosensitive medium exposed to the laserbeam as well as the dark area of the original image and the remainingportion of the photosensitive drum to thereby form a synthesizedelectrostatic image. This synthesized image is then developed into avisible image by developing means 13 using a developer chiefly composedof charged toner particles, after which the visible image is transferredonto paper or other appropriate transfer medium 11 by utilization of afurther corona discharger 76. The thus transferred image is fixed byfixing means 46 such as an infrared ray lamp or hot plate to obtain anelectrophotographically printed image 47. On the other hand, theinsulating layer surface after the image transfer is cleaned by cleaningmeans 48 to remove any residual charged particles to make thephotosensitive drum 8 ready for reuse. Formation and development of theelectrostatic latent image are similar to those in the previouslydescribed embodiments.

By the above-described electrophotographic process, a first exposureimage by the laser beam (FIGS. 17(a), 20(a), 21(a) and 22(a)) and asecond exposure image by the finite format original (FIGS. 17(b), 20(b),21(b) and 22(b)) are synthesized in the manner as shown in FIGS. 16(a)to 16(i), and FIGS. 20 to 23. The thus synthesized image, when developedby the use of a toner of opposite polarity to that of the primarycharge, will represent the form as shown in FIGS. 17(d), 20(d), 21(d)and 22(d). When the same synthesized image is developed by the use of atoner in the polarity as that of the primary charge, the developed imagewill represent the form as shown in FIGS. 17(c), 20(c), 21(c) and 22(c).The hatch-lined portions in FIGS. 17(a), 20(a), 21(a) and 22(a) andFIGS. 17(b), 20(b), 21(b) and 22(b) represent dark areas, hence it isusually in the system of FIG. 17 that the image synthesis actually takesplace. In the system of FIG. 17, when the first exposure for the laserbeam is not effected, but only the second exposure for the originalimage is conducted, there will be obtained a reproduced image. Also,when the first exposure is carried out and then the second exposurefollows by the overall irradiation, there will be produced only arecorded image due to the extraneous signal. The control for theseexposure operations may be done by a print control section shown in theblock diagram of FIG. 23. In FIG. 23, the signal control section 82processes extraneous input signals 84 and delivers instruction signals70 and 71 to a first exposure control portion 86 and a second exposurecontrol portion 69, respectively. In accordance with these signals, thefirst exposure 72, the second exposure, namely, the original imageexposure, 73, and the overall exposure 74 are controlled.

A further embodiment of the present invention is illustrated in FIGS. 24and 25. This embodiment, in addition to the various means in theprevious embodiment, has means for changing over the original imagebetween the first and the second exposures, by which the synthesizedrecording as well as the inverted reproduction have been made possibleby a single apparatus.

In FIGS. 24 and 25, the image of a predetermined format 35 is directedby a light path change-over mirror 63 into one of stationary mirrors 75and 64, and selected at either a first exposure position or a secondexposure position so as to expose a photosensitive drum 8. Thischange-over means enables a positive or an inverted image to be obtainedreadily. Since the synthesis of the laser light image and the originalimage by the first and the second exposures has already been describedwith respect to the previous embodiment, the synthesis of the image withthe first exposure will now be described by reference to FIGS. 26(a)through 28(d). FIGS. 26(a), 27(a) and 28(a), and FIGS. 26(b), 27(b) and28(b) indicate either one of the laser light image and the originalimage. When the two images (a) and (b) are simultaneously irradiated,subjected to the overall exposure at the second exposure position, andare developed, there will be obtained a synthesized image as shown inFIGS. 26(c), 27(c), and 28(c) and FIGS. 26(d), 27(d) and 28(d), whereinthe image (c) is resulted from the positive development while the image(d) is resulted from the inversion development. The system of FIG. 28 isusual.

When the image shown in FIG. 28(b) is made a developed image, andcompared with that shown in FIG. 17(b), it will be apparent thatpositive synthesis or inverted synthesis, and reproduction can beaccomplished easily by changing over the exposure position, even in casethe same developer is used.

It will thus be appreciated that the present invention provides a noveland epoch-making apparatus which can easily accomplish, at high speedand with high quality the image recording, synthesis, and reproductionwithout using any additional expedient.

Further, when the inversion development is to be carried out in themethod of the present invention for overlaying the light beam image andthe original image at the first exposure position, the original image tobe overlaid must be a negative image.

It is also possible to obtain a negative copy from a positive originalimage through the inversion development by taking advantage of thefunction of the present apparatus as a reproduction machine. Suchnegative copies may be used as the originals to be overlaid on the lightbeam image. In the past, production of the negative copies had to berelied on experts in the field which was very inconvenient. According tothe above-illustrated embodiments of the present invention, however, itis possible to obtain very easily the image records for overlayingpurpose from ordinary positive originals by a single apparatus.

Although, in the foregoing, the present invention has been explained indetail in reference to several preferred embodiments, it should beunderstood that these embodiments are merely illustrative and notrestrictive, and that any change and modification may be made in so faras they do not deviate from the spirit and scope of the presentinvention as recited in the appended claims.

What is claimed is:
 1. An image information recording apparatus,comprising:means for reading an image carried on an image carryingmember and for generating a first electric signal representing theimage, said reading and first signal generating means including meansfor projecting light to the image carrying member in an elongateprojection area extending across the image carrying member, means formoving the light projected by said projecting means in a directionsubstantially perpendicular to the length of the elongate projectionarea, and photoelectric transducer means for receiving the projectedlight from the image carrying member to generate a first electric signalrepresentative of the image; means for combining the first electricsignal with a second electric signal representing information to berecorded, which is different from the image of said image carryingmember, to form a third electric signal; means for generating a laserbeam modulated in accordance with the third electric signal; and meansfor scanning a recording medium with the laser beam.
 2. An apparatusaccording to claim 1, wherein said reading and first signal generatingmeans includes means for generating a binary signal corresponding to thesignal generated by said photoelectric transducer means, the binarysignal thereby constituting the first electric signal.
 3. An apparatusaccording to claim 1, wherein said reading and first signal generatingmeans includes means for generating a binary signal which corresponds tothe signal generated by said photoelectric transducer means and whichhas a level different from that of the second electric signal, thebinary signal being the first electric signal.
 4. An apparatus accordingto claim 1, wherein said reading and first signal generating meansincludes means for converting the signal generated by said photoelectrictransducer means to a binary signal, and means for inverting the binarysignal to form the first electric signal.
 5. An apparatus according toclaim 1, wherein said first electric signal is an analog signal.
 6. Animage information recording apparatus, comprising:a movableelectrophotographic photosensitive member; means for scanning an imageof an image carrying member in one direction and in a directionsubstantially perpendicular to said one direction to generate a firstelectric signal representing the image, said scanning and first signalgenerating means including means for projecting light to the imagecarrying member in a projection area elongated in said one direction anda photoelectric transducer means for receiving the projected light fromthe image carrying member to generate an electric signal, wherein saidimage carrying member moves in the direction substantially perpendicularto said one direction; means for combining said first electric signalwith a second electric signal representing information to be recorded,which is different from the image of said image carrying member, to forma third signal; means for generating a laser beam modulated inaccordance with the third electric signal; deflecting means fordeflecting the laser beam; means for rotating said deflecting means at aconstant speed; and means for focusing the laser beam onto theelectrophotographic photosensitive member.
 7. An apparatus according toclaim 6, wherein said scanning and first signal generating meansincludes means for generating a binary signal corresponding to thesignal generated by said photoelectric transducer means, the binarysignal thereby constituting first electric signal.
 8. An apparatusaccording to claim 6, wherein said scanning and first signal generatingmeans includes means for generating a binary signal which corresponds tothe signal generated by said photoelectric transducer means and whichhas a level different from that of the second electric signal, thebinary signal being the first electric signal.
 9. An apparatus accordingto claim 6, wherein said scanning and first signal generating meansincludes means for converting the signal generated by said photoelectrictransducer means to a binary signal, and means for inverting the binarysignal to generate the first electric signal.
 10. An apparatus accordingto claim 6, wherein said first electric signal is an analog signal.